/*
 * gleem -- OpenGL Extremely Easy-To-Use Manipulators.
 * Copyright (C) 1998-2003 Kenneth B. Russell (kbrussel@alum.mit.edu)
 *
 * Copying, distribution and use of this software in source and binary
 * forms, with or without modification, is permitted provided that the
 * following conditions are met:
 *
 * Distributions of source code must reproduce the copyright notice,
 * this list of conditions and the following disclaimer in the source
 * code header files; and Distributions of binary code must reproduce
 * the copyright notice, this list of conditions and the following
 * disclaimer in the documentation, Read me file, license file and/or
 * other materials provided with the software distribution.
 *
 * The names of Sun Microsystems, Inc. ("Sun") and/or the copyright
 * holder may not be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED "AS IS," WITHOUT A WARRANTY OF ANY
 * KIND. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND
 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, NON-INTERFERENCE, ACCURACY OF
 * INFORMATIONAL CONTENT OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. THE
 * COPYRIGHT HOLDER, SUN AND SUN'S LICENSORS SHALL NOT BE LIABLE FOR
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 * COPYRIGHT HOLDER, SUN OR SUN'S LICENSORS BE LIABLE FOR ANY LOST
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 * CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND
 * REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF OR
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 * HOLDER, SUN AND SUN'S LICENSORS DISCLAIM ANY EXPRESS OR IMPLIED
 * WARRANTY OF FITNESS FOR SUCH USES.
 */

package org.gephi.lib.gleem.linalg;

/**
 * 3x3 matrix class useful for simple linear algebra. Representation
 * is (as Mat4f) in row major order and assumes multiplication by
 * column vectors on the right.
 */

public class Mat3f {
    private final float[] data;

    /**
     * Creates new matrix initialized to the zero matrix
     */
    public Mat3f() {
        data = new float[9];
    }

    /**
     * Initialize to the identity matrix.
     */
    public void makeIdent() {
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                if (i == j) {
                    set(i, j, 1.0f);
                } else {
                    set(i, j, 0.0f);
                }
            }
        }
    }

    /**
     * Gets the (i,j)th element of this matrix, where i is the row
     * index and j is the column index
     */
    public float get(int i, int j) {
        return data[3 * i + j];
    }

    /**
     * Sets the (i,j)th element of this matrix, where i is the row
     * index and j is the column index
     */
    public void set(int i, int j, float val) {
        data[3 * i + j] = val;
    }

    /**
     * Set column i (i=[0..2]) to vector v.
     */
    public void setCol(int i, Vec3f v) {
        set(0, i, v.x());
        set(1, i, v.y());
        set(2, i, v.z());
    }

    /**
     * Set row i (i=[0..2]) to vector v.
     */
    public void setRow(int i, Vec3f v) {
        set(i, 0, v.x());
        set(i, 1, v.y());
        set(i, 2, v.z());
    }

    /**
     * Transpose this matrix in place.
     */
    public void transpose() {
        float t;
        t = get(0, 1);
        set(0, 1, get(1, 0));
        set(1, 0, t);

        t = get(0, 2);
        set(0, 2, get(2, 0));
        set(2, 0, t);

        t = get(1, 2);
        set(1, 2, get(2, 1));
        set(2, 1, t);
    }

    /**
     * Return the determinant. Computed across the zeroth row.
     */
    public float determinant() {
        return (get(0, 0) * (get(1, 1) * get(2, 2) - get(2, 1) * get(1, 2)) +
            get(0, 1) * (get(2, 0) * get(1, 2) - get(1, 0) * get(2, 2)) +
            get(0, 2) * (get(1, 0) * get(2, 1) - get(2, 0) * get(1, 1)));
    }

    /**
     * Full matrix inversion in place. If matrix is singular, returns
     * false and matrix contents are untouched. If you know the matrix
     * is orthonormal, you can call transpose() instead.
     */
    public boolean invert() {
        float det = determinant();
        if (det == 0.0f) {
            return false;
        }

        // Form cofactor matrix
        Mat3f cf = new Mat3f();
        cf.set(0, 0, get(1, 1) * get(2, 2) - get(2, 1) * get(1, 2));
        cf.set(0, 1, get(2, 0) * get(1, 2) - get(1, 0) * get(2, 2));
        cf.set(0, 2, get(1, 0) * get(2, 1) - get(2, 0) * get(1, 1));
        cf.set(1, 0, get(2, 1) * get(0, 2) - get(0, 1) * get(2, 2));
        cf.set(1, 1, get(0, 0) * get(2, 2) - get(2, 0) * get(0, 2));
        cf.set(1, 2, get(2, 0) * get(0, 1) - get(0, 0) * get(2, 1));
        cf.set(2, 0, get(0, 1) * get(1, 2) - get(1, 1) * get(0, 2));
        cf.set(2, 1, get(1, 0) * get(0, 2) - get(0, 0) * get(1, 2));
        cf.set(2, 2, get(0, 0) * get(1, 1) - get(1, 0) * get(0, 1));

        // Now copy back transposed
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                set(i, j, cf.get(j, i) / det);
            }
        }
        return true;
    }

    /**
     * Multiply a 3D vector by this matrix. NOTE: src and dest must be
     * different vectors.
     */
    public void xformVec(Vec3f src, Vec3f dest) {
        dest.set(get(0, 0) * src.x() +
                get(0, 1) * src.y() +
                get(0, 2) * src.z(),

            get(1, 0) * src.x() +
                get(1, 1) * src.y() +
                get(1, 2) * src.z(),

            get(2, 0) * src.x() +
                get(2, 1) * src.y() +
                get(2, 2) * src.z());
    }

    /**
     * Returns this * b; creates new matrix
     */
    public Mat3f mul(Mat3f b) {
        Mat3f tmp = new Mat3f();
        tmp.mul(this, b);
        return tmp;
    }

    /**
     * this = a * b
     */
    public void mul(Mat3f a, Mat3f b) {
        for (int rc = 0; rc < 3; rc++) {
            for (int cc = 0; cc < 3; cc++) {
                float tmp = 0.0f;
                for (int i = 0; i < 3; i++) {
                    tmp += a.get(rc, i) * b.get(i, cc);
                }
                set(rc, cc, tmp);
            }
        }
    }

    public Matf toMatf() {
        Matf out = new Matf(3, 3);
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {
                out.set(i, j, get(i, j));
            }
        }
        return out;
    }

    @Override
    public String toString() {
        String endl = System.getProperty("line.separator");
        return "(" +
            get(0, 0) + ", " + get(0, 1) + ", " + get(0, 2) + endl +
            get(1, 0) + ", " + get(1, 1) + ", " + get(1, 2) + endl +
            get(2, 0) + ", " + get(2, 1) + ", " + get(2, 2) + ")";
    }
}
